Deriving the Kelly Criterion to Maximise Profits

A million years ago, when you could still find video poker games with 100%+ theoretical return or poorly thought-out promotions offering enough cash-back to get you over 100%, we'd calculate the Kelly number for a given opportunity -- the bankroll necessary to ride out hills and valleys in favorable situations.

Spoiler: It's almost always 3-4x the value of a royal flush. So you needed $12-16k if you were playing a $1-per-coin game with a 1% edge at a pretty good clip.

And what do you earn with perfect play in that situation? The princely sum of around $30 an hour.

Isn't that a pretty good return? Multiply by 100: this is the equivalent of $3,000/hour on $1.2M of capital!